FIELD OF THE INVENTION
This invention lies in the field of washing coal with water only in a shallow bottomed centrifugal separating cyclone of circular cross-section having a cylindrical portion with a diameter to height ratio of 0.8 to 1.3, preferably 0.90 to 0.95, the cyclone fitted with a single inlet pipe, a shallow dish below the cylindrical portion, a single bottom orifice fitted to the shallow dish and a fixed vortex finder leading to an outlet at the top for removal of washed coal. Gravity separation under streamlined flow is accomplished with light coal particles at a gravity value down to about 1. using crushed coal ranging in size from 1-3/4".times.0 down to 3/8".times.0.
The invention also lies in the field of providing an easily insertable abrasion resistant separator bottom having unique toughness and wear resistance characteristics to provide trouble-free, efficient coal washing based on the special material characteristics and the critical geometry of the shallow bottom dish which adapts it to fit in a closely contoured relationship to the cylindrical portion of the cyclone.
The invention deals with minimal water to the pumps and separators while separating heavy solids from light solids in centrifugal cyclone gravity separation.
Further, the invention lies in the field of rebuilding cyclones to include the insertable dish and orifice and set the critical adjustments of the invention.
The invention also lies in the field of cleaning ores other than coal to rid them of impurities by taking advantage of the newly discovered efficiency and capacity taught in the present application.
In particular, the field of the invention is that of my Case No. 1, Ser. No. 860,330, filed Dec. 14, 1977, now U.S. Pat. No. 4,219,409, but added to Case No. 1 teachings are the empirically determined critical values above identified to extend the use of the invention to greater efficiency and economy to meet the operating requirements for cleaning of any commercially producible coal with water only and to reduce its non-combustible ingredients prior to using the coal in a utility or steel plant, in a pipeline for transportation or for industrial or home heating.
The invention also deals with ecology in washing raw coal to get clean coal while removing refuse, this eliminating cancer causing materials and other pollutants. Similarly, cancer causing asbestos is removed from taconite. Cancer inducing fly ash by the test for "bacteria mutation" is removed from the coal before burning.